Compsognathus, one of the smallest known nonavian dinosaurs, was about the size of a present-day turkey. Its name refers to the delicacy of its jaw, but its fossils suggest that it was a delicate animal overall.

There are two known skeletons of Compsognathus. The first, found in 1859, was from the late Jurassic lithographic limestone of southern Germany. This animal lived alongside Archaeopteryx. It lay on a slab of stone, its legs nearly perfectly preserved and its last meal, a lizard, in its ribcage. The second skeleton was found near Canjuers, in France.

Compsognathus may have had two-fingered hands. While the French specimen had three metacarpal bones (bones in the palm), it is not clear that all three had phalanges (finger bones) attached. Some paleontologists argue that this small, agile predator was - like tyrannosaurids, but unlike any other theropods - effectively two-fingered. However, because the hands were not intact, it is possible that the phalanges from the third fingers were either not found or not identified.

The hand of the French specimen is too poorly preserved to provide any conclusive evidence. What is certain is that Compsognathus's closest relative, Sinosauropteryx, possessed three-fingered hands.

Compsognathus has long played a central role in studies of bird origins. Because it was found in the same deposits as Archaeopteryx, and was roughly the same size, it provides an easy comparison between a primitive coelurosaur and a primitive bird. During the 19th century, similarities between these two fossils were often cited as evidence of the dinosaur - bird link. Like Sinosauropteryx, Compsognathus may well have had short, fibrous, featherlike structures on its body, although there is no direct evidence of these in the known specimens.

Michael Crichton's novels Jurassic Park and The Lost World gave Compsognathus a venomous bite that allowed groups of these fictional dinosaurs to overwhelm larger prey. It is much more likely, though, that this small animal confined itself to catching small victims and that it used its clawed fingers and toothy jaws to do so.